I have a strange blank box that appears at the top of the screen when I start some applications: Virtualbox was the first, but now others have started to do this too. It is very annoying, as it just sits there on all workspaces, and I have to restart to get rid of it. The 'desktop' button makes all the windows go away, but not this one.
My setup is: Mint 13 64-bit Cinnamon 1.4 on a Dell 14z i5 with 6GB RAM.
I've attached a screenshot of my desktop. The box sits just above my browser window. What is it and how to stop this issue please?
Otherwise I am very happy with Cinnamon..